CN101438172A

CN101438172A - Current probing system

Info

Publication number: CN101438172A
Application number: CNA2007800166471A
Authority: CN
Inventors: K·A·斯蒂芬斯; M·J·门德; J·S·丹迪; T·J·夏普
Original assignee: Tektronix Inc
Current assignee: Tektronix Inc
Priority date: 2006-05-08
Filing date: 2007-05-04
Publication date: 2009-05-20
Anticipated expiration: 2027-05-04
Also published as: JP2009536742A; WO2007131186A3; WO2007131186A2; EP2016427A2; JP4753323B2; US7294995B1; CN101438172B; US20070257657A1; EP2016427B1

Abstract

A current probing system has a current probe and a detachable adapter. The current probe has a probe body with electrically conductive contacts that mate with electrically conductive contacts on the adapter. Leads extend from the adapter for coupling to a current carrying conductor. The leads can connect to a plug that is coupled to a current diverting device for coupling a current signal to the current probe. The adapter may also include a switch that selectively couples the current signal to the current probe when the adapter is mated with the current probe. The contacts of the current probe are coupled to a current sensing circuit which generates a voltage output representative of the current signal. The voltage output is coupled to an oscilloscope via an electrical cable.

Description

Current probing system

Technical field

The present invention relates generally to current probe and more specifically relate to the current probe system that uses with oscillograph that is used for gathering current signal from current.

Background technology

Used transformer technology to measure the electric current that in conductor, flows with the current probe that oscillograph uses.Transformer have the toroidal core that defines the aperture and can be core solid or closed or magnetic core a side with respect to other side be movably open or divide (split) core.This allows do not needing to make current pass the aperture of transformer under the situation that current and circuit are disconnected.Current pass in the magnetic core the aperture and as the elementary winding of transformer.One side of secondary winding wounded core.The current-induced that flows in current is linked to the magnetic flux of magnetic core and secondary winding.Magnetic flux causes the electric current that results from the secondary winding, and this electric current produces and the opposite magnetic flux of magnetic flux that is produced by the electric current that flows in current.In passive current probe, stride the transformer terminal connecting resistance that produces the output of AC voltage and make the alternating current decline (drop) that produces by secondary winding.Voltage output is coupled to oscillographic input channel by cable.Oscillograph processes voltage signal is used to show the expression of current signal.

Because transformer is the AC signal coupling apparatus, the transformer cut-off frequecy of passband is on the DC level.For allowing current probe sensing DC and low-frequency current signal, the active electric current probe is included in Hall (Hall) means for influencing in the magnetic core of transformer.Hall effect device is to be positioned in the magnetic core so that magnetic flux in the magnetic core and the vertical substantially semiconductor of Hall Plate.The voltage as a result that the Hall effect that bias voltage is imposed on Hall Plate and caused by the flux in the magnetic core produces is coupled to the input of differential amplifier.Power amplifier is coupled in the single-ended output of amplifier, and this power amplifier produces the proportional electric current output of the electric current that produces with hall effect device.With the output of Hall device amplifier or alternatively the output of power amplifier be coupled to Secondary winding of transformer and produce flux so that be derived from the output current of the secondary winding of flowing through of amplifier, this flux is opposite with input magnetic flux on the whole frequency passband of hall effect device.In one embodiment, with the side that secondary winding is coupled in the output or the power amplifier output of Hall effect, wherein the side in addition of winding is coupled to transformer and amplifier circuit.In another embodiment, the output of Hall effect amplifier is coupled to secondary same side as amplifier circuit by resistor.With the input of capacitor-coupled, be used for the electric current of blockage source from Hall effect amplifier to the broad band amplifier in amplifier circuit.In the input of operational amplifier to the output of Hall effect amplifier and the output summation of broad band amplifier, this operational amplifier have provide with Secondary winding of transformer in the feedback resistor through the proportional voltage output of combination current.The voltage output of operational amplifier is to the AC of magnetic core flux and measuring of DC component.Operational amplifier output is coupled to oscillographic input channel by cable.In a word, the active electric current probe is branch ring (split-ring) transformer type.United States Patent (USP) 3,525,041,5,477,135 and 5,493,211 have described above current sensing circuit.

Be to measure electric current by conductor, current probe must with the conductor series coupled.When current was fixed on the substrate of the circuit trace (circuit trace) on the circuit board for example, this proved difficulty.The general process of the electric current in the metering circuit trace is to disconnect (break) trace and one section electric wire of welding between the trace fracture.Make electric wire be passed in aperture in the transformer of current probe, wherein electric wire is as the elementary winding of transformer.Another process is to make the circuit board in band trace gap and at the either side in gap square pin is installed.During the proper testing of circuit board, conductive jumper (jumper) is coupled to square pin.When requiring testing current, wire jumper is removed and one section electric wire of connection between square pin.As previously, electric wire is used as the elementary winding of the transformer in the current probe.

Transformer based on current probe has many restrictions on the electric current of measuring through the circuit trace on the circuit board.The sensitivity of current measurement as a result is subject to the repeatability of placing the repeatable of electric wire and the branch core that aligns exactly when opening and closing divide core on the same position in the magnetic core at transformer on identical position with accuracy.Needed is current probing system, and this current probing system has been eliminated the use as the staple for electric wire of the elementary winding of current probe.In addition, current probing system should be provided at current probe is connected to dirigibility on the current.In addition, current probing system should be provided at the sensitivity of current measurement and the bigger repeatability on the accuracy.

Summary of the invention

Therefore, be used for having current probe and the adapter that is installed on the current probe from a kind of current probing system that satisfies above demand that uses with oscillograph of current collection current signal.Current probe has sonde body and places first and second conductive contacts of an end of sonde body.First and second conductive contacts are suitable for and the current series coupled.First and second conductive contacts are coupled to current sensing circuit, and the output signal that is used for being created in the electric current that current flows is represented.The output signal that is derived from current sensing circuit is coupled to oscillograph by the cable of end in addition that extends from sonde body.Adapter has and is suitable for being installed in the shell on the sonde body and has first and second conductive lead wires of extension from shell.In the lead-in wire each has first electric contact that is used to be coupled to current and places second electric contact of one of first and second conductive contacts that are used in the shell with current probe coupling.

First electric contact of first and second conductive lead wires can be coupled to the plug that is suitable for engaging conductive contact, this conductive contact is as the on-off element in being coupled to the current diverting device of current, wherein through the current signal of current and at the current signal of second place coupling through current probe, this second place is produced at least one the downward pressure in the conductive contact of current diverting device by plug current diverting device in primary importance coupling.This downward pressure makes the conductive contact of current diverting device break away from the second current diverting device position.

In first electric contact of conductive lead wire each also be included in the electrically conductive socket that has the hole in the electrically conductive socket in case with the either side that is installed in the non-conductive gap in the current on square pin connector coupling.In first electric contact of first and second conductive lead wires each also can form contact pad, and this contact pad is fixed to current regularly on the either side in non-conductive gap.Wherein stride the lead-in wire of the non-conductive gap coupling adapter in the current, first end that places switch in the adapter shell to have to be electrically coupled to a conductive lead wire and optionally to be coupled to one of current probe contact, be coupled to other conductive lead wires and optionally be coupled to second end of other current probe contacts.Switch armature optionally is coupled first and second ends.Switch have when adapter shell separates with sonde body switch armature with the conductive lead wire electric coupling together primary importance and when adapter shell is installed on the sonde body switch armature make the second place of the mutual decoupling zero of conductive lead wire.When adapter shell is installed on the sonde body, the current probe contact is coupled to first and second ends of switch.Adapter can comprise that also the preferably form between first and second ends that place switch is first and second voltage clamps of diode, is used to make the electric arc of striding tip side that is caused by the induction recoil to minimize.

In a preferred embodiment, the conductive contact that places sonde body and adapter shell is by placing separately the contact array of socket to form.Each socket has first and second parts of contact array, with this contact array electric coupling together to form first and second conductive contacts in the sonde body and first and second conductive contacts in the adapter shell.Socket coupling in sonde body and adapter shell is together so that with first and second conductive contacts in the sonde body and the coupling of first and second conductive contacts in the adapter shell.

Current sensing circuit can be implemented as Magnetic Sensor, and this Magnetic Sensor is coupled to first and second conductive contacts so that the magnetic flux of sensed current signal and be coupled to amplifier circuit so that produce the output signal be illustrated in the electric current that flows in the current.Magnetic Sensor can be taked the form of transformer or fluxgate.Transformer has magnetic core, wherein with primary and secondary winding wounded core.Make elementary winding coupled first and second conductive contacts so as from current received current signal and in magnetic core and secondary winding induced flux so that be created in current signal output the secondary winding that is coupled to amplifier circuit.Transformer also can comprise the magnetic-electric transducer that is placed in the magnetic core, magnetic flux in this magnetic-electric transducer and the magnetic core interacts so that produce the DC that is illustrated on the current voltage signal to low-frequency current signal, and wherein voltage signal is coupled to amplifier circuit.

When coming together to read together with appended claims and appended accompanying drawing, from following detailed description, purpose of the present invention, advantage and new feature are tangible.

Description of drawings

Fig. 1 is the skeleton view according to current probing system of the present invention.

Fig. 2 illustration be used for the various adapters of current probing system.

Fig. 3 is the decomposition diagram that is used for the adapter of current probing system.

Fig. 4 is schematically showing at the circuit of the adapter that is used for current probing system.

Fig. 5 is the skeleton view of the adapter that uses of current transfer (diverting) device that can be on being installed in current.

Fig. 6 is the schematically showing of current sensing circuit in current probing system.

Fig. 7 is the schematically showing of another current sensing circuit in current probing system.

Fig. 8 is the schematically showing of further current sensing circuit in current probing system.

Embodiment

Fig. 1 is the skeleton view that is used for obtaining from current 14 current probing system 10 of current signal that uses with oscillograph 12.Current probing system 10 has the current probe 16 of band sonde body 18, and current sensing circuit places sonde body 18.Current sensing circuit is electrically coupled to first and second conductive contacts of an end that places sonde body 18.Adapter 20 optionally is attached on the sonde body 16.Adapter 20 has shell 22, the first and second

conductive lead wires

24 and 26 and extends from shell 22.Conductive cable 28 extends the end in addition from sonde body 18, is used for output signal is coupled to oscillograph 12 and electric power is offered sonde body 16 from current sensing circuit.Preferably conductive cable 28 is coupled to current probe control enclosure 30, this current probe control enclosure 30 is coupled to one of a plurality of input signal channels 32 of oscillograph 12.Each input signal channel 32 has jack interface 34, and wherein each interface has conductive contact and coaxial signal socket (jack).Current probe control enclosure 30 have with the plug interface 36 of jack interface 34 coupling and have with jack interface 34 in respective electrical contact point and the electric contact and the coaxial signal jack of coaxial signal

jack interface.Interface

34 and 36 electric power is offered current probe 16 and be provided at current probe 16 and oscillograph 12 between

communication.Interface

34 and 36 also is provided at the signal path between current probe 16 and the oscillograph 12.

Various types of

electric contacts

38,40 are provided on first and second

conductive lead wires

24 and 26 of current probe adapter 20, and this will describe in more detail following.Electric contact is suitable for being electrically coupled to one of a plurality of

electric connectors

42,44 that for example are installed on the current 14 of circuit trace that forms on the circuit board 46 or the like.The non-conductive gap 48 that

electric connector

42,44 is striden in the current 14 is positioned on the current 14.Electric connector 42 has the square pin 50 on the either side that is installed in non-conductive gap 48, and this square pin 50 is electrically coupled to current 14.Electric wire jumper 52 is positioned in the square pin 50, is used for when current probe adapter 20 is not coupled to current 14, striding non-conductive gap 48 couple current signals.Electric connector 44 be with will be at the coaxial socket 54 of following coax plug in greater detail coupling.Contact pad (pad) 56 also can be formed on the current 14 on the either side in non-conductive gap 48.Removable conductive foil 58 is fixed to contact pad, is used to stride non-conductive gap 48 couple current signals.When current probe adapter 20 is coupled to current 14, conductive foil 58 is removed from current 14.

Fig. 2 illustration be used for the representative example of the adapter 20 of current probing system 10.The sonde body 18 of current probe 16 have the substantial rectangular shape from front portion 60 that sonde body 18 outside surfaces fall in.In a preferred embodiment, anterior 60 have socket 62, and this socket 62 has the contact array of first and second conductive contacts that form current probe 16.Other parts that the part of contact array forms first conductive contact and contact array form second conductive contact.The front portion 60 that sonde body 18 is mated and be fixed to by breech lock (latching) element 64 on the front portion 60 that places extension in the front portion 60 of adapter shell 22 and sonde body 18.Declutcher control lever 66 is positioned on the sonde body 18, breaks away from when this declutcher control lever 66 when primary importance moves to the second place makes latch component 64 and adapter shell 22.

The shell 22 of adapter 20 has aperture 68, and the cable 70 that comprises first and second

conductive lead wires

24 and 26 extends from the hole 68.One end of each in the

conductive lead wire

24 and 26 disposes

electric contact

38,40, is used for being coupled to current 14 by one of electric connector on current 14 42,44 or contact pad 56.In a configuration, electric connector is the electrically conductive socket (socket) 72 that is attached on the conductive lead wire 24,26.Mate on the either side in electrically conductive socket 72 and the non-conductive gap 48 of square pin 50 in current 14.In another configuration, electric contact the 38, the 40th extends the conductive electric wire 74 from the end of conductive lead wire 24 and 26.Conductive electric wire 74 can be the end of lead-in wire, and perhaps they can form contact pad, are used for being fixed on the either side in non-conductive gap 48 contact pad 56 of current 14.Still in another configuration,

conductive lead wire

24 and 26 is electrically coupled to coax plug 76, coaxial socket 54 couplings on this coax plug 76 and the non-conductive gap 48 that is installed in current 14.

Referring to Fig. 3, show the decomposition diagram of adapter 20.Preferably, adapter shell 22 is formed by half-shells 80, and this half-shells 80 is mated together to clamp (capture) circuit board 82 therein.The cable 70 that comprises first and second

conductive lead wires

24,26 runs through the aperture 68 in the adapter shell 22.

Conductive lead wire

24,26 is electrically coupled to circuit board 82.Ground lead 84 also extends from cable 70 and is connected to outer shield conductor.Have with socket 62 in sonde body 18 in the socket 86 of the similar contact array of contact array be installed on the circuit board 82.Socket 62 and 86 is devices of coupling, wherein contact array in the socket 62 and the contact array in other sockets 86 coupling.Also switch 88 is installed on the circuit board 82.Use switch 88 with adapter 20 with contact pad 74 and electrically conductive socket 72.As what illustrate best by schematically showing of Fig. 4, by the circuit trace on circuit board 82 with

conductive lead wire

24,26, socket 86 with switch 88 electric coupling be in the same place.

In the schematic diagram of Fig. 4,

socket

62 and 86 illustrates the array separately of contact 90 and 91.First and

second parts

92 and 93 of the array of contact 90 are bound together first and second

conductive contacts

94 and 95 that are coupled to the current probe 16 of current sensing circuit 96 with formation.First and

second parts

97 and 98 of the array of contact 91 are bound together to form first and second

conductive contacts

99 and 100 of adapter 20.First conductive contact 99 is electrically coupled to first end 101 of switch 88 and second conductive contact 100 is electrically coupled to second end 102 of switch 88.Also first conductive lead wire 24 is electrically coupled to switch terminals 102 and second conductive lead wire 26 is electrically coupled to switch terminals 101.Switch armature 103 is electrically coupled to switch terminals 102 and is selectively coupled to switch terminals 101.Switch armature 103 mechanically is coupled to the plunger (plunger) 104 of extension from switch 88.

Catching diode

105 and 106 is

striden switch terminals

101 and 102 electric coupling.

When adapter 20 was not connected to current probe body 18, switch armature 103 was coupled switch contact 101 and 102.Electric switch connection as a result is coupled first and second conductive lead wires 24 and 26.When adapter 20 was connected to current 14, this provided the current path of striding the non-conductive gap 48 in the current 14.At first make

socket

62 and 86 contact 90 contact electric contact adapter 20 and current probe body 18 couplings with 91 array.The contact that makes switch plunger 104 contact sonde bodies 18 is inserted in the continuation of adapter 20 on sonde body 18.The continuation of adapter 20 insertion depression of plunger 104 makes switch armature 103 and switch contact 101 break away from sonde body 18.This disconnects the short circuit of

striding switch contact

100 and 101 and makes current 14 and current sensing circuit 96 series coupled by conductive lead wire 24 and 26.The configuration of switch on the circuit board 82 88 and socket 86 make switch armature 103 disconnect with the contacting of switch terminals 101 before the disconnection of

socket

86 and 62

contact

90 and 91 array is contacted.The catching

diode

105 and 106 that is installed on the circuit board 82 is provided, is used to make the electric arc of striding switch contact 101 and tip side 10 that causes by induction recoil (inductive kick-back) to minimize.

Fig. 5 is the skeleton view with adapter 20 of the conductive lead wire that is electrically coupled to coax plug 76.One of

conductive lead wire

24,26 is electrically coupled to the center electrical conductor in the coax plug 76 and another lead-in wire is electrically coupled to the conduction ectosome of plug 76.The center electrical conductor of coax plug 76 and conduction ectosome mutually insulated.Electric connector 44 is the current diverting device with coaxial socket 54, wherein center pit 108 and outer conducting sleeve 109 insulation.Conductive contact 110 extends out from coaxial socket by reverse direction, adopts scolder that conductive contact 110 is fixed to current 14 regularly on the either side in non-conductive gap 48.Conductive contact 110 extends in the coaxial socket 54, wherein one of conductive contact stride that center pit 108 extends in case overlap joint (overlap) other conductive contacts 110 with as on-off element.One of conductive contact 110 is electrically coupled to conducting sleeve 109 and is electrically coupled to current 14 by being formed on contact pad 112 other sides in non-conductive gap 48 on the circuit board 46 by the conductive lead wire 111 that extends from coaxial socket 54 by the direction vertical with other conductive contacts 110.Conductive contact 110 is striden the non-conductive gap 48 couple current signals in the current 14 in the first current diverting device position.

Coax plug 76 is fixed to coaxial socket 54, wherein the conduction ectosome of coax plug 76 is coupled to the outer conducting sleeve 109 of coaxial socket 54.The center electrical conductor of coax plug 76 extends in the center pit 108 of coaxial socket 54 and engages the conductive contact 110 that extends in the center pit 108.The center electrical conductor of coax plug 76 applies downward pressure to conductive contact 110 makes contact 110 and other conductive contacts 110 break away from.By one of conductive contact 110 and other conductive contact 110 transfer current signals, pass through the current sensing circuit of current probes 16 and turn back to current 14 from current 14, one of this conductive contact 110 is coupled to the central conductor of coax plug 76 and is coupled to current probe 16 by one of

conductive lead wire

24,26, and these other conductive contacts 110 are coupled to the conduction ectosome of the outer conducting sleeve 109 of coaxial socket 54 and coax plug 76 and are coupled to current probe 16 by in the

conductive lead wire

24,26 another.The coupling of coax plug 76 and coaxial socket 54 with current probe 16 with current 14 series coupled and be the second current diverting device position.Coax plug 76 is pulled up the downward pressure that will discharge conductive contact 110 from coaxial socket 54 makes contact 110 engage again mutually.The coax plug 76 of above-mentioned coaxial socket 54 and coupling is by Wallingford (fertile clever Ford), the Amphenol of CT, and Corp. is according to part number MCH-201 and MCH203 produce and market separately, as radio-frequency (RF) switch and radio-frequency probe.

Referring to Fig. 6, the current sensing circuit 96 in the current probe 16 that can be used for current probing system 10 is shown.Current sensing circuit 96 has the magnetic material toroidal core 120 that defines the aperture.First and second

conductive contacts

94 and 95 of current 14 by current probe 16 are coupled to elementary winding 122, this elementary winding 122 and current 14 series coupled.Current 14 is pressed the flux annexation by elementary winding 122 and toroidal core 120 couplings.Electric current to be measured in the current 14 produces magnetic flux and is linked to secondary winding 124 in toroidal core 120.One end of secondary winding 124 is coupled to ground, wherein other end is coupled to the inverting input of trans-impedance amplifier 126.The inverting input of trans-impedance amplifier 126 is striden the output terminal that the current signal path 128 that hinders resistor 130 is coupled to amplifier 126 by having.Thereby elementary winding 122, magnetic core 120 and secondary winding 124 are used as transformer 132.Magnetic-electric transducer 134 is placed in magnetic core 120 vertical with the line of flux roadbed basis of magnetic core 120.Preferably, magnetic-electric transducer 134 is the thin film semiconductor's hall effect devices of second opposite end that have first opposite end of being coupled to bias generator 136 and be connected to the difference input of amplifier 138.Preferably, amplifier 138 is the high gain differential amplifiers with low noise and high common mode inhibition.The single-ended output of differential amplifier 138 is coupled to the noninverting input of trans-impedance amplifier 126.The bias control signal that the demagnetization by current sensing circuit can also be produced imposes on differential amplifier 138 by offset voltage line 140.

Electric current in the elementary winding 122 produces the magnetic flux that is linked to secondary winding 124 and hall effect device 134 in the magnetic core 120 of transformer 132.The DC or the low frequency component of the electric current that flows in elementary winding 122 produce potential difference (PD) between second opposite end of hall effect device 134.The voltage output of hall effect device 134 is coupled to the difference input of amplifier 138.The output of amplifier 138 is coupled to the noninverting input of trans-impedance amplifier 126.The voltage that hall effect device 134 produces makes the variable signal level (level) that causes in the noninverting input of trans-impedance amplifier 126 can produce the voltage level of respective change in the output of trans-impedance amplifier 126.Voltage in output place of trans-impedance amplifier 126 is created in the electric current that produces in the current signal path 128 of the secondary winding 124 that is coupled to transformer 132.Electric current that flows in secondary winding 124 and the opposite current that flows in elementary winding 122 that produces magnetic flux in magnetic core 120, the electric current that flows in secondary winding 124 produce the electric current that flows in elementary winding 122 magnetic flux becomes zero.This DC has kept the inverse current of the process current signal path 128 of the DC that equals in the transformer 132 elementary windings 122 or low current signal to low-frequency feedback loop.

The high fdrequency component of the electric current that flows in elementary winding 122 is created in the electric current of inducting on the direction in the magnetic field in for example producing magnetic core 120 in the secondary winding 124, and this magnetic field is opposite with the field that electric current in the elementary winding 122 produces.The electric current of inducting in secondary winding 124 is coupled to the anti-phase input of trans-impedance amplifier 126.Because anti-phase input is virtual earth (virtualground), electric current in secondary winding 124 is striden the output that resistance resistor 130 is coupled to trans-impedance amplifier 126 by current signal path 128 processes, and this trans-impedance amplifier 126 is created in the exporting through amplification voltage of high fdrequency component of the electric current that flows in the elementary winding 122 and represents.Trans-impedance amplifier 126 when act on produce bucking current in case make DC to the magnetic flux in the magnetic core 120 at low current frequency place become zero power amplifier and be used as higher frequency trans-impedance amplifier the two.The output of trans-impedance amplifier 126 is arrived oscillograph 12 through conductive cable 28.

Fig. 7 is schematically showing of another current sensing circuit 96.With previous components identical in Fig. 7 by identical mark.Current sensing circuit 96 has the magnetic material toroidal core 120 that defines the aperture.First and second

conductive contacts

94 and 95 of current 14 by current probe 16 are coupled to elementary winding 122, this elementary winding 122 and current 14 series coupled.Current 14 is pressed the flux annexation by elementary winding 122 and toroidal core 120 couplings.Electric current to be measured in the current 14 produces magnetic flux and is linked to secondary winding 124 in toroidal core 120.Thereby elementary winding 122, magnetic core 120 and secondary winding 124 are used as transformer 132.Magnetic-electric transducer 134 is placed in magnetic core 120 vertical with the line of flux roadbed basis of magnetic core 120.Preferably, magnetic-electric transducer 134 is the thin film semiconductor's hall effect devices of second opposite end that have first opposite end that is coupled and be connected to the difference input of amplifier 138 between bias generator 136 and ground.Preferably, amplifier 138 is the high gain differential amplifiers with low noise and high common mode inhibition.The power amplifier 150 that an end of secondary winding 124 is coupled in its output is coupled in the single-ended output of differential amplifier 138.The input that the in addition end of secondary winding 124 is coupled to voltage gain amplifier 152 by transformer 154 summing junctions.

Electric current in the elementary winding 122 produces the magnetic flux that is linked to secondary winding 124 and hall effect device 134 in the magnetic core 120 of transformer 132.The DC or the low frequency component of the electric current that flows in elementary winding 122 produce potential difference (PD) between second opposite end of hall effect device 134.The amplifier 138 that power amplifier 150 is coupled in its output is coupled in the voltage output of hall effect device 134.Power amplifier 150 produces the electric current output of being coupled to secondary winding 124.Be derived from the electric current that flows in secondary winding 124 of power amplifier 150 and the opposite current that flows in elementary winding 122 that produces magnetic flux in magnetic core 120, the electric current that flows in secondary winding 124 produces the electric current that flows in elementary winding 122 magnetic flux becomes zero.Be illustrated in DC in the elementary winding 122 of transformer 132 or low current signal through the inverse current of secondary winding and be coupled to the input of voltage gain amplifier 152 by transformer 154 summing junctions.

The high fdrequency component of the electric current that flows in elementary winding 122 is created in the electric current of inducting on the direction in the magnetic field in for example producing magnetic core 120 in the secondary winding 124, and this magnetic field is opposite with the field that electric current in the elementary winding 122 produces.The electric current of inducting in secondary winding 124 is coupled to the input of voltage gain amplifier 152 by transformer 154 summing junctions.The electric current that flows in secondary winding 124 that is derived from power amplifier 150 makes DC become zero to the magnetic flux in the magnetic core 120 of low-frequency current signal.The electric current of being inducted in secondary winding 124 by the electric current that flows in elementary winding 122 makes the magnetic flux in the magnetic core 120 of high-frequency current signal become zero.Be induced at the electric current that in secondary winding 124, flows that is derived from power amplifier 150 with higher frequency transition range (transitionrange) between the electric current in the secondary winding 124 produce be derived from two sources at the summed electric current in transformer 154 summing junction places.The voltage output of voltage gain amplifier 152 is coupled to oscillograph 12 through conductive cable 28.

Fig. 8 is schematically showing of further current sensing circuit 96.Current 14 is coupled to the input winding 160 of fluxgate 162 by first and second

conductive contacts

94 and 95 of current probe 16, this input winding 160 and current 14 series coupled.Fluxgate 162 has the cylinder shape magnetic core 164 of input winding 160 around it.Contact rod 166 is passed cylinder shape magnetic core 164 coaxial placements and is coupled to the driving circuit 168 that is coupled to oscillator 170.Place magnetic test coil 172 around cylinder shape magnetic core 164, the magnetic flux that is used to detect the magnetic flux of the current signal on the input winding and is derived from the signal of oscillator 170.Magnetic test coil 172 is coupled to testing circuit 174, and this testing circuit 174 has from the frequency mixer 176 of oscillator 170 received signals, and the frequency of this signal is the twice of frequency that is applied to the signal of contact rod 166.Frequency mixer 176 is coupled to and is coupled to by termination resistor 182 low-pass filter (LPF) 178 of output amplifier 180.

Driving circuit 168 produces the vibration drive currents, and this vibration drive current locates to make magnetic core 164 saturated so that magnetic flux leaves (leave) magnetic core 164 and align with contact rod 166 (align) at the peak value (peak) of driving current signal.In the meantime, the magnetization degree of core 164 in the vertical descends.When drive current during near zero crossing, magnetic flux passes magnetic core 164 once more.In the meantime, the magnetization degree of core 164 in the vertical increases.The direction of the magnetic flux in the magnetic core and density change and change according to drive current.For each cycle of drive current, the voltage output of adopting the current drive signal that is applied to fluxgate 162 to be induced in the input winding 160 has two cycles.The current signal that is applied to input winding 160 is created in the modulated voltage output that the current signal on the input winding is represented to the modulation of the magnetic flux in the magnetic core at magnetic test coil 172 places.Exporting through modulation voltage on magnetic test coil 172 is coupled to frequency mixer 176.Frequency mixer 176 will be that the oscillator signal of the twice of drive current frequency multiplies each other through modulation voltage output and frequency.The output filtering of 178 pairs of frequency mixer of low-pass filter is so that provide and import the proportional voltage of electric current that flows in the winding 160.Accept filter signal and produce voltage output of output amplifier 180 through amplifying.Above-mentioned current sensing circuit and can be made amendment to above circuit only as an example without departing from the present invention.

The current probing system that has current probe and can adhere to adapter has been described.Current probe have sonde body and with adapter on the conductive contact of conductive contact coupling.Lead-in wire extends out so that be coupled to current from adapter.Lead-in wire can be connected to the plug that is coupled to current diverting device so that current signal is coupled to current probe.Adapter can also comprise switch, and this switch optionally is coupled to current probe with current signal when adapter and current probe coupling.The contact of current probe is coupled to the current sensing circuit of the voltage output expression that produces current signal.Voltage output is coupled to oscillograph by cable.

To those skilled in the art, under the situation that does not break away from ultimate principle of the present invention, obviously can carry out many changes to the details of the above embodiment of the present invention.Therefore, scope of the present invention should only be determined by appended claims.

Claims

1. current probing system that uses with oscillograph that is used for gathering from current current signal comprises:

Have the current probe of sonde body and first and second conductive contacts of an end that places sonde body, wherein first and second conductive contacts are suitable for and the current series coupled;

Be coupled to the current sensing circuit of first and second conductive contacts, the output signal that is used for being created in the electric current that current flows is represented; And

Extension is from the conductive cable of end in addition of sonde body, through being coupled to receive output signal and to be used to be coupled to oscillograph from current sensing device; And

Has the adapter that is suitable for being installed in the shell on the sonde body, have first and second conductive lead wires of extension from shell, wherein each in first and second conductive lead wires has first electric contact that is used to be coupled to current and places second electric contact of one of first and second conductive contacts that are used in the shell with current probe coupling.

2. current probing system as claimed in claim 1, wherein first electric contact with first and second conductive lead wires is coupled to the plug that is suitable for engaging conductive contact, this conductive contact is as the on-off element in being coupled to the current diverting device of current, wherein current diverting device is coupled through the current signal of current probe through the current signal of current and in the second place in the primary importance coupling, this second place is produced at least one the downward pressure in the conductive contact of current diverting device by plug, and this downward pressure makes the conductive contact of current diverting device break away from the second current diverting device position.

3. current probing system as claimed in claim 1, wherein adapter also comprises the switch that places in the adapter shell, this switch has one of second electric contact of being coupled to first and second conductive lead wires and optionally is coupled to first end of one of first and second conductive contacts of current probe, be coupled in second electric contact of first and second conductive lead wires another and optionally be coupled in first and second conductive contacts of current probe another second end and the armature that first and second ends optionally are coupled, wherein switch have when adapter shell separates with sonde body armature with the first and second conductive lead wire electric coupling together first position of the switch and when adapter shell is installed on the sonde body armature make the second switch position of the mutual decoupling zero of first and second conductive lead wires, when adapter shell is installed on the sonde body, first and second conductive contacts of current probe are coupled to first and second ends of switch.

4. current probing system as claimed in claim 3, wherein current have that in first electric contact of the square pin that is installed on the either side in the non-conductive gap in current on the current and first and second conductive lead wires each also is included in the electrically conductive socket that has the hole in the electrically conductive socket in case with the square pin connector coupling that is installed on the current.

5. current probing system as claimed in claim 3, wherein current have in first electric contact of the non-conductive gap in current and first and second conductive lead wires each also comprise contact pad, this contact pad is connected to each in first and second conductive lead wires and is fixed to current regularly on the either side in non-conductive gap.

6. current probing system as claimed in claim 3, wherein adapter also comprises first and second voltage clamps between first and second ends that place switch, is used to make the electric arc of striding tip side that is caused by the induction recoil to minimize.

7. current probing system as claimed in claim 6, wherein voltage clamp comprises diode.

8. current probing system as claimed in claim 1, wherein place the conductive contact of sonde body to form by the contact array that places socket, wherein with first's electric coupling of contact array together to form first conductive contact in the sonde body and the second portion of contact array be coupled to form second conductive contact in the sonde body, and place first and second conductive contacts of adapter shell also to comprise the contact array that places socket, wherein with first's electric coupling of contact array together to form first conductive contact and the second portion of contact array be coupled to form second conductive contact, the socket coupling in sonde body and adapter shell is so that be coupled first and second conductive contacts in the sonde body and first and second conductive contacts in the adapter shell.

9. current probing system as claimed in claim 1, wherein current sensing circuit also comprises Magnetic Sensor, and this Magnetic Sensor is coupled to first and second conductive contacts so that the magnetic flux of sensed current signal and be coupled to amplifier circuit so that produce the output signal be illustrated in the electric current that flows in the current.

10. current probing system as claimed in claim 9, wherein Magnetic Sensor also comprises the transformer with elementary winding, secondary winding and magnetic core, wherein make elementary winding coupled first and second conductive contacts in case from current received current signal and in magnetic core and secondary winding induced flux so that be created in current signal output the secondary winding that is coupled to amplifier circuit.

11. current probing system as claimed in claim 10, wherein the magnetic core of transformer be annular and define the aperture, wherein place elementary winding around the part of the toroidal core of transformer.

12. current probing system as claimed in claim 10, wherein transformer also comprises magnetic-electric transducer, this magnetic-electric transducer is placed in the magnetic core of transformer and interacts so that produce the DC that is illustrated on the current voltage signal to low-frequency current signal with magnetic flux in the magnetic core, and wherein voltage signal is coupled to amplifier circuit.

13. current probing system as claimed in claim 9, wherein Magnetic Sensor also comprises fluxgate.